grant all privileges on nextcloud.* to nextcloud@'localhost' identified by 'password';

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]>

flush privileges;

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]>

exit

Bye

[6]

Access to the URL [http://(your hostname or IP address)/nextcloud/] from a client computer with Web browser.
Then following screen is shown. Add an admin account for ownCloud, and also click [MySQL/MariaDB] in database section and
input username or database name for MariaDB. If it's OK all, Click [Finish Setup] to proceed.

[7]

This is NextCloud main page. It's possible to use NextCloud as cloud storage.